<html><head>
<script src="https://unpkg.com/react/umd/react.development.js" crossorigin></script>
<script src="https://unpkg.com/react-dom/umd/react-dom.development.js" crossorigin></script>
<script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
</head><body>
<div id="root"></div>
<script type="text/babel">
const root = ReactDOM.createRoot(
document.getElementById('root')
);
function tick() {
const element = (
<div>
<h1>Hello, world!</h1>
<h2>It is {new Date().toLocaleTimeString()}.</h2>
</div>
);
root.render(element);
}
setInterval(tick, 1000);
</script>
</body></html>